This interactive stacked bar chart visualizes earthquake counts by magnitude range across U.S. states for selected years. A dropdown menu lets viewers switch between 2017 and 2018 data, triggering a 750ms transition that updates bar positions and total labels. Built with D3 v5, the chart uses `d3.stack()` and `d3.scaleBand()`, rendering SVG rects and text elements. Color encoding distinguishes three magnitude categories (7.0+, 6–6.9, 5–5.9), with data loaded from a CSV file via `d3.csv`.